cyberknife stereotactic treatment...image guidance limited to pre-treatment, patient set-up only •...

Cyberknife Stereotactic Treatment

Eugene Lief, Ph.D.

Christ Hospital

Jersey City, New Jersey

USA

DISCLAIMER:

I am not affiliated with any vendor and did not receive any financial support from any vendor.

I am not recommending any particular product.

CyberKnife® System

CyberKnife from Accuray, Inc.

Cyberknife Capabilities• As a robotic radiosurgery system, the CyberKnife

enables to target tumors anywhere in the body with sub-millimeter accuracy.

• Autonomous robotic ability to track, detect and correct for tumor and patient movement throughout the treatment

• Dynamically delivering radiation in sync with real-time tumor motion

• CyberKnife System provides a pain-free treatment alternative without the use of head and body frames.

Tumor Sites

• CyberKnife® System can treat tumors in: Brain, Spine, Lungs, Liver, Pancreas, Prostate

• No head and body frames or other immobilization devices.

• The number of CyberKnife extracranial treatments grew by over 185% between 2004 and 2006.

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Growing Popularity

Autonomous Robotics• au•ton•o•mous ro•bot•ics [aw-ton-uh-muhs roh-bot-iks]–noun

a: an electro-mechanical device capable of making intelligent decisions with limited or no human guidance

b: a mechanized tool with the independent ability to respond and react to a dynamic environment based upon sensory input.

• CyberKnife® System allows to track unpredictable tumor motion due to normal bodily functions, such as movement due to digestive functions around the prostate. It tells when the tumor moves even when the patient is stationary. The System shows [in real-time] tumor position from the beginning to the end of the treatment and automatically corrects for tumor movement.”

Continuous Image Guidance

Without the need for staff intervention or treatment interruption, the CyberKnife® System continuously works in concert with the treatment delivery system to instantlytrack, detect and correct –managing possible target movements throughout the treatment.

Flexible Robotic ManeuverabilityDriven by continual

imaging and intelligent movement corrections, the CyberKnife’srobotic manipulator automatically places the linear accelerator to a wide possible range of positions–allowing access to any tumor from multiple directions

Dynamic Motion TargetingWith constant updates of

target position throughout the respiratory cycle, the beams are synchronized in real-time to the target position while adapting to changes in breathing patterns–delivering highly conformal radiation with small margins and high accuracy.

Intelligent Patient PositioningThe robotic patient

positioning system automatically moves the patient to the exact treatment position with immediate accuracy–providing greater setup precision while significantly streamlining the patient setup process.

Room Setup

4D Treatment Optimization and Planning System

Takes into account not only the movement of the target but also the movement and deformation of the surrounding tissue.

Xchange™ Robotic Collimator Changer

Automatically exchanges collimators robotically, maintaining highly efficient treatment process

Xsight™ Lung Tracking System

Tracks the movement of lung tumors directly without fiducials, with precision, reliability and self-adjusting repeatability.

Synchrony® Respiratory Tracking System

Continuously synchronizes beam delivery to the motion of the tumor, allowing to significantly reduce margins while eliminating the need for gating or breath-holding techniques.

RoboCouch™ Patient Positioning System

Robotically aligns patients precisely with six degrees of freedom, reducing patient setup times and enabling faster treatments.

X-ray Sources

The low-energy X-ray sources generate orthogonal images to determine the location of bony landmarks, implanted fiducials or soft tissue targets throughout the entire treatment.

Image Detectors

The flush mounted detectors capture high-resolution anatomical images throughout the treatment. These live images are continually compared to previously captured DRR’s to determine real-time patient positioning and target location. Based on this information, the robotic manipulator instantly corrects for any detected movement.

Robotic Manipulator

The high precision robotic manipulator capable of delivering repeatable sub-millimeter accuracy, positions the linear accelerator in almost any direction providing non-coplanar and non-isocentricbeam delivery.

Linear Accelerator

This compact, light weight 6MV X-ray linear accelerator with an output of 600 MU/min, precisely delivers highly collimated beams of radiation, providing superior conformality

MultiPlan™ Treatment Planning System

This intuitive workflow-based workstation designed for radiosurgery, enables the creation of plans that have high conformality and coverage with steep dose gradients.

Radiosurgery vs. Radiotherapy

Cumulative dose tumor control

Tumor ablationClinical Intent

3 – 20 millimeters< 1 millimeterTypical Targeting Accuracy

5 – 10150 – 200Typical # of Unique Beams Per Fraction

30 – 45 fractions1 – 5 fractionsTypical # of Fractions

Low dose

(~ 2 Gy per fraction)

High dose

(~ 6 to 25 Gy per fraction)

Average Dose Per Fraction

RadiotherapyRadiosurgery

Dose Escalation for Tumor Ablation Necessitates:

Large Non-Coplanar Beam Delivery• Ability to diversify beam trajectories to reduce risks of dose toxicity

• Agility to target tumors from a high volume of unique angles

Extreme Targeting Accuracy• Ability to deliver sub-millimeter mechanical accuracy

• Ability to deliver sub-millimeter tumor targeting accuracy

Intracranial and ExtracranialApplications

UnlimitedAbility to Fractionate

Immobilization devices used. Low dose per fraction reduces need for accuracy

Utilizes gating / breath-holding techniques resulting in large contour margins and unnecessary healthy tissue exposure

Limited clockwise / counter-clockwise gantry mobility enables a single plane typically delivering 7 unique beam angles

• Additional planes can be achieved with manual couch yaw rotations. Patient / gantry collision potential and the impractical nature of manual patient positioning has resulted in little or no clinical adoption

Typically limited to MV portal imaging on a weekly basis

5 – 20 millimeters

Radiation Therapy Systems

Stereotactic Frames

Moving Tumor Targeting

Non-Coplanar Delivery Capabilities

Image Guidance

Targeting Accuracy Varian ClinacVarian Clinac®®

Elekta SynergyElekta Synergy®®Siemens PRIMUSSiemens PRIMUS®®

TomoTherapy HiTomoTherapy Hi--ART SystemART System®®

Radiation Delivery System Comparison


UnlimitedUnlimitedAbility to Fractionate

Required in most Intracranial & Extracranial cases



• Additional planes can be achieved with manual couch yaw rotations, however without image guidance due to patient / OBI collisions - resulting in less than ideal targeting accuracy. Further, the impractical nature of manual patient positioning has resulted in little or no clinical adoption

Image guidance limited to pre-treatment, patient set-up only

• High resolution kV imaging / cone-beam CT

Intracranial and Extracranial


Radiation Therapy Systems Adapted for Radiosurgery









Stereotactic Frames



Image Guidance

Applications

Targeting Accuracy Varian TrilogyVarian Trilogy™™

Elekta AxesseElekta Axesse™™BrainLAB NovalisBrainLAB Novalis®®

Typically limited to a single fraction due to time, resource, and pain constraints


Requires invasive frames in all cases

N/A

Hemisphere with fixed collimators enables a non-coplanar workspace capable of delivering a maximum of 201 (190 Perfexion™) unique beam angles

None, relies exclusively on target’s fixed relative position to the stereotactic frame

• Frame mechanical accuracy may introduce 1.2-1.9 mm error (*Maciunas)

Intracranial only

• Limited spine capabilities (C1 & C2) Perfexion™ only

< 1 millimeter

Dedicated Cobalt 60 Radiosurgery Systems




• Additional planes can be achieved with manual couch yaw rotations, however without image guidance due to patient / OBI collisions - resulting in less than ideal targeting accuracy. Further, the impractical nature of manual patient positioning has resulted in little or no clinical adoption


• High resolution kV cone-beam CT












Stereotactic Frames



Image Guidance

Applications

Targeting Accuracy Elekta Gamma KnifeElekta Gamma Knife®®

Elekta PerfexionElekta Perfexion™™American Radiosurgery GammaARTAmerican Radiosurgery GammaART--60006000™™

* RJ Maciunas, RL Galloway Jr, JW Latimer. The application accuracy of stereotactic frames. Neurosurgery 35(4): 682–695, Oct 1994



UnlimitedTypically limited to a single fraction due to time, resource and pain constraints


Requires invasive frames in all cases

N/A

Hemisphere with fixed collimators enables a non-coplanar workspace capable of delivering a maximum of 201 (190 Perfexion™) unique beam angles

None, relies exclusively on target’s fixed relative position to the stereotactic frame

• Frame mechanical accuracy may introduce 1.2-1.9 mm error (*Maciunas)

Intracranial only

• Limited spine capabilities (C1 & C2) Perfexion™ only

< 1 millimeter

Dedicated Cobalt 60 Radiosurgery Systems




• Additional planes can be achieved with manual couch yaw rotations, however without image guidance due to patient / OBI collisions -resulting in less than ideal targeting accuracy. Further, the impractical nature of manual patient positioning has resulted in little or no clinical adoption


• High resolution kV imaging / cone-beam CT












No frame requiredStereotactic Frames

Delivers tightly contoured beams synchronized precisely to tumor motion resulting in minimal healthy tissue exposure


Robotic mobility enables a large non-coplanar workspace capable of seamlessly delivering more than 1200 unique beam angles without treatment interruption or the need to manually reposition the patient


Continual image guidance throughout the treatment

• High resolution kV imaging

• Automatically track, detect and correct for tumor and patient movement

Image Guidance

Intracranial and ExtracranialApplications

< 1 millimeter for stationary tumors

< 1.5 millimeters for moving tumors

Targeting Accuracy

Dedicated Robotic Radiosurgery Systems

Accuray Incorporated Accuray Incorporated CyberKnifeCyberKnife®® SystemSystem

* RJ Maciunas, RL Galloway Jr, JW Latimer. The application accuracy of stereotactic frames. Neurosurgery 35(4): 682–695, Oct 1994

Multi-Plan TPS

• An intuitive workflow-based treatment planning software designed for radiosurgery

• Enables excellent conformality and coverage with steep dose gradients.

• Using images from multiple modalities, including CT, MR, PET and 3D Rotational Angiography.

• Up to four image sets including a reference CT, up to three additional CT, MR, PET and/or 3D Rotational Angiography image sets.

• Supports image sets in axial, sagittal, coronal and oblique orientations.

• Fusion is performed automatically using a normalized mutual information based algorithm or manually using anatomical and other reference

• the user to verify the quality of the registration result.

Planning Templates

Delineate Volumes for Tracking

Approve Beam Data

Select Planning Options

Evaluating and Finalizing the Plan

Introducing Small Changes

Simplified Contouring

• Create customized planning templates that can be used when

delineating volumes of interest (VOI) on any displayed 2D planes

(axial, sagittal or coronal) using fused image sets.

• Delineation includes basic tools, such as drawing and bumper tools, and

advanced tools such as Magic Wand™ and Smart Curve.™

• Use these and other tools to delineate multiple structures in a single VOI (e.g.cavities and bifurcated structures).

• Other tools enable generation of anisotropic volume expansion and tuning structures with just a few mouse clicks.

Plan Optimization• Choose the appropriate tracking option–6D Skull

Tracking, Fiducial Tracking, Synchrony®Respiratory Tracking, Xsight™ Spine TrackingSystem or the Xsight Lung Tracking System

• Set dose constraints to create an optimized treatment plan using forward or inverse planningtechniques and a choice of powerful optimization algorithms.

Once a Plan is Generated• View isocontours on every slice in every plane; view and

interrogate the dose volume histogram (DVH) for the target and for each critical structure

• Select 4D optimization tools to account for tissue deformation in lung treatments

• Review plan statistics, such as conformality and homogeneity indices, and 3D representations of the beam and patient geometry

• Visualize the actual treatment delivery in action

• Select beams singly or in groups and manually modify any treatment parameter

• Compare high resolution plans side-by-side to determine which provides the best treatment for the patient

QA and Commissioning• Ability to create QA plans for end-to-end testing of the

CyberKnife

• Phantom overlay of individual treatment plans for plan QA

• Ability to export a treatment beam parameter list, enabling patient specific manual dose calculation checks

• The ability to view and approve beam data that is stored in the CyberKnife database prior to using this data to generate plans

• DICOM inter faces:– Import and Export DICOM Image series

– Import and Export DICOM RT Structure Set

– Export DICOM RT Dose

cyberknife stereotactic treatment...image guidance limited to pre-treatment, patient set-up only •...

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